Silver halide complexing agents

ABSTRACT

Photographic silver halide can be stabilized with certain organic sulfonium, organic sulfoxonium, organic ammonium, organic phosphonium, organic boronium, and/or organic siliconium halides of mixtures of these. These can be employed in a photographic element, processing solution or processing web. They are useful in combination with a nonaqueous, low-melting solvent, e.g. succinimide, sulfamide, urea, or acetamide.

United States Patent [72] Inventors Joseph S. Yudelson;

Randall E. Mack, both of Rochester, N.Y. [21] Appl. No. 575,548 [22]Filed Aug. 29, 1966 [45] Patented Oct. 26, 1971 [73] Assignee EastmanKodak Company Rochester, N.Y.

[54] SILVER HALIDE COMPLEXING AGENTS 16 Claims, No Drawings [52] U.S.Cl96/61, 96/ 109 [51] lnt.Cl G03c 5/38, G030 1/34 [50] Field of Search96/61, 109, 95

[56] References Cited UNITED STATES PATENTS 3,347,675 11/1967 Herm eta1. 96/67 2,238,631 4/1941 Dersch 96/109 2,238,632 4/1941 Dersch 96/1092,288,586 6/1942 Dersch 96/109 3,093,479 6/1963 Olivares 96/50 3,161,50612/1964 Becker 96/109 3,177,237 4/1965 Muetterties 260/4482 3,177,2404/1965 Muetterties 252/95 3,179,517 4/1965 Tregillus 96/50 3,212,89910/1965 Kennard 96/95 3,243,295 3/1966 Vogt 96/61 Primary ExaminerNormanG. Torchin Assistant ExaminerMary F. Kelley AttorneysW. H. J. Kline andBernard D. Wiese ABSTRACT: Photographic silver halide can be stabilizedwith certain organic sulfonium, organic sulfoxonium, organic ammonium,organic phosphonium, organic boronium, and/or organic siliconium halidesof mixtures of these. These can be employed in a photographic element,processing solution or processing web. They are useful in combinationwith a nonaqueous, low-melting solvent, e.g. succinimide, sulfamide,urea, or acetamide.

SILVER HALIDE COMPLEXING AGENTS This invention relates to silver halidecomplexing agents and in particular to the stabilization and fixing ofsilver halide sensitized photographic materials.

The usual procedure employed in the processing of lightsensitive silverhalide photographic elements is development of the latent silver imagefollowed by fixing to remove residual light-sensitive silver salts. Ifrapid processing of films and papersis desired and'extreme permanence isnot required, the unexposed silver halides may be left in the photographand converted into compounds which are relatively inert to light, heat,and humidity. This type of rapid processing is known as stabilizationand the criteria for judging its effectiveness are the stability of theresulting photographic image to moist incubation and light. Many of theknown stabilization processes utilize complexing agents which haveserious limitations. Often, opaque complexes are formed or thecomplexing agent bleaches the silver image. Some of these complexingagents are activated by water and thus, such agents cannot beincorporated into aqueous gelatin-silver halide emulsions withoutadversely affecting the sensitometric characteristics of the emulsion orthe lightsensitive layer. These water-activated complexing agents arenot suitable for dry-processing techniques. in addition, few silverhalide stabilizers have been found which operate satisfactorily indiffusion transfer processes. In this invention, silver halidecomplexing agents have been found which are free from these undesirablecharacteristics, and which can be used effectively to stabilize or fix aphotographic element.

it is an object of this invention to provide photographic silver halidestabilization and fixing compositions which form stable, transparentsilver halide complexes, and which can be in the form of either aqueousor nonaqueous solutions.

Another object is to provide a process for the stabilization ofphotographic images.

A further object is to provide a process for fixing photographic imageswhich can employ aqueous or nonaqueous fixing baths.

Still another object is to provide a simplified process for thestabilization of a photographic silver halide element which requiresonly heating of the element.

A further object is to provide photographic silver halide stabilizationcompositions which can be employed in a photographic diffusion transferprocess.

Still another object is to provide photographic silver halide elementscontaining a heat-activated stabilization composition which will enablesuch elements to be stabilized by heating alone.

A further object is to provide a class of silver salt complexing agentswhich have a slow rate of stabilization in cold aqueous solutions, butwhich will stabilize an exposed photographic element quite rapidly inhot aqueous solutions.

Still another object is to provide a class of silver halide complexingagents which are odorless, unusually stable to adverse changes of heat,light, and humidity, which have little tendency to bleach silver images,and which do not cause tack or stickiness in processed elements.

Another object is to provide a processing web containing silver halidecomplexing agents for processing photographic elements.

Still further objects will become apparent from the followingspecification and claims.

According to our invention, it has been found that light-sensitivesilver halide photographic elements can be stabilized with a solutioncontaining a stabilizing amount of a complexing agent selected from thegroup consisting of organic sulfonium halides, organic sulfoxoniumhalides, organic ammonium halides, organic phosphonium halides, organicboronium halides, organic siliconium halides, or mixtures thereof.Certain of these organic complexing agents may also be defined inaccordance with the following formulas:

R1 R: Q Rt 69 A x or m-lu-R, x

wherein A is S; A is N or P;

X is a halide ion;

R R and R are lower alkyl; R, is lower alkyl or aryl, e.g. phenyl. Inthe above definition of R R' amino includes substituted amino groups,hydroxy includes ether linkages, alkyl includes substituted alkylgroups, and aryl includes substituted aryl groups.

Especially preferred complexing agents falling within the above formulainclude tetraethylammonium bromide, 2- hydroxyethyltrimethylammoniumbromide, tetraethylammonium chloride, ethyltrimethylammoniurn bromide,tetramethylammonium bromide,- tetrapropylammonium iodide, methylaminehydrobromide, trimethylamine hydrobromide, tetraethylphosphoniumbromide, n-butyltriphenylphosphonium bromide, and trimethylsulfoniumbromide. The complexing agents can be present in the solution in anyamount which will effect stabilization and preferably comprise about 5to about 40 percent by weight of the solution.

Solution of the silver halide complexing agent may be made either inwater or in a suitable nonaqueous, low-melting solvent. The complexingagents of the invention have a slow rate of stabilization in cold,aqueous solutions, but when a photographic element is treated'with ahot, aqueous solution of the complexing agent, rapid stabilizationoccurs.

Useful nonaqueous solvents which are liquid and will promotestabilization at room temperature include formamide,N,'N-dimethylformamide, dimethylsulfoxide, and tetramethylene sulfone.Low-melting solvents, such as succinimide, sulfamide, acetamide, andurea, which are solids at room temperature, are also quite useful. Theycan be coated onto the photographic element or a separate processing webalong with the stabilizer, so that stabilization can be effected merelyby heating the element, or bringing it into contact with the hotprocessing web.

in a preferred embodiment of our invention, the silver halide complexingagents are incorporated in a low-melting, nonaqueous solvent, and apolymeric binder through which the melted solvent can diffuse. Thismixture is coated as an image stabilization layer upon a light-sensitivephotographic silver halide emulsion layer. The low-melting solvent issolid at room temperature, and the complexing agents contained thereinare inactivev Upon heating, the solvent melts and allows diffusion ofthe complexing agent into the photographic emulsion layer where itreacts with unexposed silverhalide to cause stabilization.

The combination of succinimide and tetraethylammonium bromide ortetraethylphosphonium bromide when used as a stabilizing composition hasan exceptionally low tendency toward bleaching the silver image.Succinimide forms a clathrate which is extremely non deliquescent withtetraethylammonium bromide and with tetraethylphosphonium bromide, andthus fading is inhibited. Images stabilized with this composition do notfade as quickly as those fixed with alkali thiosulfates.

Quaternary ammonium compounds have been used in photographic processesof the prior art. In US Pat. No. 3,093,479 of Olivares et al., grantedJune 1 1, I963, fixing ofa photographic image is followed by treatmentwith a solution of a quaternary ammonium halide to prevent image fadingand overall yellowing and to protect the image from microbacterialdeterioration. The quaternary salt, which is used in smallconcentrations ('1-2 percent), combines with any residual thiosulfatefrom the fixing process, apparently forming an insoluble, immobilemolecule which cannot react with aerial or residual sulfide ion. In ourinvention, quaternary ammonium compounds are used in larger amounts assilver halide complexing agents and react with the unexposed silverhalide to form stable complexes, probably of the typeQeaAgx aThus, thequaternary salts act as stabilizers with the complexed silver halideeither remaining in the element or being removed by washing.

U.S. Pat. Nos. 2,238,631 and U.S. Pat. No. 2,238,632 of Dersch et al.,granted Apr. 15, 1941, and U.S. Pat. No. 2,288,586 of Dersch et al.,granted June 30, i942, describe the use of certain quaternaryphosphonium iodides, ternary sulfonium iodides, and quaternary ammoniumiodides to control yellow fog in photographic emulsions. These compoundsare used in small amounts to prevent colloidal silver formed in theprocessing baths from forming a yellow deposit on the emulsion. In ourinvention, our compounds are used in larger amounts as complexing agentsto prevent the printout of silver halide, an effect occurring afterprocessing. Two kinds of stabilizing agents which form complexes withsilver halides are known in the prior art-those which produce insolublesilver halide complexes and those which produce soluble complexes.Insoluble silver halide complexes, which are usually opaque and, thus,generally not useful for stabilizing photographic film records, areformed from the reaction of thioglycolic acid, thiosalicylic acid, andsimilar mercapto compounds with silver halides. Alkali thiosulfates,alkali thiocyanates, thiourea, and certain thiourea derivatives convertsilver halides into soluble complexes. The complexing agents of theinvention constitute a new class of silver halide stabilizers quiteunlike those of the prior art. They have a broad range of applicationsand avoid many of the limitations of the known stabilizers.

The stabilizing agents of our invention can be incorporated intophotographic silver halide emulsion layers, or coated in separate layerscontiguous to the emulsion layer. When incorporated into the emulsionlayer, the stabilizing agents of the invention can be convenientlycoated from aqueous solutions at or below room temperature withoutprestabilization of the emulsion. When these stabilizing agents arecoated in a separate layer, solid, low-melting, nonaqueous solvents areused to provide a photographic element which may be stabilized merely byheating.

The silver halide complexing agents of the invention may also beutilized in stabilizing or fixing baths, using either nonaqueoussolvents or hot water. A wide range of nonaqueous solvents may be usedsuch as alcohols, ketones, nitriles,

etc.

The processing solutions of the invention can also be incorporated intoa separate processing web. Stabilization can then be effected bycontacting the web having the solution imbibed therein with the exposedphotographic element. Alternatively, a dry web containing the complexingagent and a low-melting solvent such as succinimide, sulfamide, urea oracetamide, can be contacted with a photographic element and heated tomobilize the complexing agent.

A developing agent may also be included in the photographic element orprocessing web which contains the stabilizing agent. The silver halidedeveloping agents which may be used include those commonly known assilver halide reducing agents such as, for example 3-pyrazolidones,including 1- phenyl-3-pyrazolidone, l-phenyl-4,4-dimethyl-pyrazolidone,etc., ascorbates, including sodium isoascorbate, p-phenylenediamine,hydroquinones, N-methyl-p-aminophenol sulfate, catechol, etc. Especiallypreferred developing agents are l-phenyl-3-pyrazolidone and sodiumisoascorbate. Thus, if a developer is added to an element or processingweb which contains the complexing agents of the invention, developmentand stabilization can be achieved in a single processing step.

Another use of the silver halide complexing agents of the invention isin diffusion transfer processes. In such processes, a photographicelement is first exposed and developed. The unexposed silver halide inthe nonimage areas of the element are then complexed or stabilized anddiffused to a receiving sheet containing active nuclei. In contact withthese active nuclei, the silver complexes dissociate providing silverions which can then be developed to a silver image on the receivingsheet. The complexing agents employed for this purpose must be capableof picking up and transferring all of the unexposed silver halide, andmore importantly, the resulting complex must dissociate in contact withthe nuclei in the receiving sheet. Most silver halide stabilizers andcomplexing agents form complexes which will not readily or sufficientlydissociate in contact with the receiving sheet. The silver complexesformed with the stabilizing compositions of this invention dissociatereadily in contact with the receiving sheet nuclei and thus provide anextremely useful diffusion transfer System.

When used to fix or stabilize a photographic image, the complexingagents of the invention need not be dissolved in only one solvent, butcan also be dissolved in mixtures, complexes, or eutectics composed ofseveral solvents. By a proper choice of solvents or mixtures ofsolvents, many variables in nonaqueous processing such as processingtemperature, maximum density, fog level, and gamma can be adjusted asdesired.

The photographic silver halide emulsions of the photographic elementswhich can be stabilized in this invention can be sensitized using any ofthe well-known techniques in emulsion making, for example, by digestingwith naturally active gelatin or various sulfur compounds and/or goldcompounds. The emulsions can be sensitized with salts of noble metals ofGroup Vlll of the Periodic Table which have an atomic weight greaterthan The emulsions can be of the surface-sensitive or internallysensitive type. The emulsions can also contain speed-increasing addendasuch as polyethylene glycols or thioether sensitizers.

The emulsions of the photographic elements which can be stabilizedaccording to our invention can also contain conventional addenda such asgelatin plasticizers, hardeners and coating aids. These emulsions areuseful -in X-ray and other nonoptically sensitized emulsions, and canalso be used in orthochromatic, panchromatic and infrared sensitiveemulsions. The addenda can be added to the emulsion before or aftersensitizing dyes, if any, are used. Various silver halides can be usedas the sensitive salt, such as silver bromide, silver iodide, silverchloride, or mixed silver halides such as silver chlorobromide or silverbromoiodide. The emulsions can be used in photographic elements intendedfor color photography, and thus can contain color-forming couplers, orused as emulsions to be developed by solutions containing couplers orother color-generating materials, or emulsions of the mixedpacket type,as disclosed by Godowsky, U.S. Pat. No. 2,698,794, or emulsions of themixed-grain type, such as disclosed by Carroll et al., U.S. Pat. No.2,592,243.

In the photographic elements which may be stabilized according to thisinvention, a wide variety of emulsion vehicles and dispersing agents forsilver halide grains may be employed singly or in combination with eachother, for example, gelatin, colloidal albumen, cellulose derivativesand synthetic resins, such as polyvinyl compounds. Examples of typicalcolloids which may be used are poly(vinyl alcohol), hydrolyzed poly(vinyl acetate), hydrolyzed cellulose ester, water-soluble ethanolaminecellulose acetate, polyacrylamide, copolymers having a combinedacrylamide content of 3-60 percent, copolymers of alkyl acrylate andacrylic acid, a vinyl alcohol copolymer containing urethane carboxylicacid groups or containing cyano-acetyl groups, or polymeric materialwhich results from polymerizing a protein or saturated acrylated proteinwith a monomer having a vinyl group such as disclosed by lllingsworth,U.S. Pat. No. 2,852,382 Such polymeric addenda may be employed aslatices or hydrosols in the preparation of the photographic emulsions ofthe photographic elements which may be stabilized'according to ourinvention.

The following examples will further illustrate the invention but are notto be construed to limit it in any way.

The first three examples illustrate the effectiveness of the complexingagents of this invention as fixing agents.

EXAMPLE 1 A percent solution of 2-hydroxyethyltrimethylammoniurn bromidewas made up in formamide. A sample of photographic paper which was madeup of a gelatino-silver chloride emulsion (containing 77 mg. silver persquare foot) was immersed in this bath for 1 minute at room temperature.This sample was washed in water for 5 minutes and analyzed for silver.The silver content was 1.6 mg. per square foot, indicating that withonly 1' minute of treatment and 5 minutes washing, practically all ofthe silver had been removed by this fixing composition.

EXAMPLE 2 A 20 percent solution of 2-hydroxyethyltrimethylammoniumbromide was made up in water. A sample of the silver chloride paper usedin example I was immersed for 4 minutes at room temperature, washed inwater for 5 minutes, and analyzed for silver. The silver content was 63mg. per square foot. This demonstrates that the quaternary salt was apoor fixing agent in water at room temperature.

EXAMPLE 3 The procedure of example 2 was repeated but with thequaternary salt solution at 90 C. and with an immersion time of 1minute. The washed sample was analyzed for silver. The silver contentwas 2.5 mg. per square foot, indicating the 2-hydroxyethyltrimethylammonium bromide to be a good fixing agent in hotwater.

EXAMPLE 4 The following example illustrates the preparation and use of aphotographic element containing a complexing agent of our invention.

The following solution was prepared:

A. Succinimide g.

l-Phenyl-S-pyrazolidone 3 g. Sodium lsoascorbate 5 g. Water g.

This solution was dispersed in 186 g. of 7 percent ethyl cellulose intoluene.

The following solution was prepared next:

B. Succinimide 6 g. Sulfamide 2 g. Tetrapropylammonium iodide 6 g. Water3 g.

Solution B was dispersed in 186 g. of 7 percent ethyl cellulose intoluene.

The two dispersions, A and B, were mixed together in equal parts andthen coated on paper having a gelatino-silver chloride emulsion using a0.0'l0-inch knife and dried. The coating was exposed to a line copynegative for 10 seconds (40 watt bulb) and heated on a 155C. mandrel for5 seconds. The print showed a good image (D 0.4) and the background waspale yellow. The print was exposed to a fluorescent desk lamp for oneweek with no deterioration of the image and no darkening ,of thebackground.

When the quaternary salt was omitted from the B solution, nostabilization was observed and the print darkened very rapidly onexposure to room light.

EXAMPLE 5 The following solution was prepared:

Succlnimlde 30 g. l-Phenyl-S-pyruolidone 3 g. Sodium lroucorhale 5 g.Tetrapropylamrnonium iodide 8 g. Water 40 g. X

lulose in toluene.

The dispersion was coated (using a 0.008-inch knife) on paper having agelatino-silver chloride emulsion. The coating was exposed to a linecopy negative for 10 seconds (40 watt bulb) and heated on a C. mandrelfor 10 seconds. An image appeared during the first few seconds ofheating. The sample was exposed to a fluorescent desk lamp (20 watt) ata distance of 6 inches for 24 hours with no deterioration of the imageand no increase in fog level.

EXAMPLE 6 The following solution was prepared: Succinirnide If) gl-PhenyH-pyrazolidone 1.5 g. Sodium lsoarcorbate 2.5 g.Tetraethylammonium bromide 6.5 g Water I!) g This solution was dispersedin 93 g. of 7 percent ethyl cellulose in toluene.

The'dispersion was coated (0.008-inch knife) on paper having agelatino-silver chloride emulsion and dried. The coating was exposed toa line copy negative for ID seconds (40 watt bulb) and then heated on a155 C. mandrel for 3 seconds. The developed image was exposed to afluorescent desk lamp (20 watt) at a distance of 6 inches for 24 hourswith no deterioration of the image and no increase in fog level.

EXAMPLE 7 A sample from example 6 was stored at 50 percent relativehumidity and 73 C. for 6 weeks. it was then exposed and heated at 155 C.for 3 seconds. The resulting developed and stabilized image showedapproximately the 'same quality as that in example 6, indicating goodshelf life of the coated paper.

EXAMPLE 8 The following solution was prepared: Succiniinide 15.0 g.Water 20.0 g. l-Phenyl-J-pyrazolidone L5 g. Sodium lsoascorbate 2.5 g.2-llydroxyethyltrimethylammonium chloride 4.0 g.

This solution was dispersed in 93 g. of 7 percent ethyl cellulose intoluene.

The dispersion was coated (0.008 inch knife) on paper having agelatino-silver chloride emulsion and dried. The coating was exposed toa line copy negative for 10 seconds (40 watt bulb) and heated on a 155C. mandrel for 3 seconds. A gray, black image resulted with a yellowbackground. The print was stable to fluorescent light with no change inthe image. or background.

EXAMPLE 9 The dispersion used in example 8 was coated (0.006-inch knife)on a substrate consisting of AgBr (30 mg. per square foot) which hadbeen vacuum-deposited on paper support. The coating was exposed to aline copy negative for 20 seconds (40 watt bulb) and heated on a 155- C.mandrel for 3 seconds. A gray, black image appeared on a tan background.The print was stable to fluorescent light with no change in the imagequality and no increase in fog.

EXAMPLE 10 This example illustrates the use of quaternary ammoniumhalides in nonaqueous solvents as the silver halide complexing agent fora diffusion transfer process.

The following solution was prepared:

Sodium lsoaacorbate 3.0 g. l-Phenyl-Ll-pyrazolidone 0.5 g.Z-Hydroxyethyltrimethylammbniun-i bromide 5.0 g. Forrnamide 50.0 ml.

A piece of paper having a gelatino-silver chloride emulsion was exposedto a line copy negative for 30 seconds in a printing box (40 watt lamp).The solution was wiped over the surface of the photographic paper with acamel's hair brush and then a ditfusion transfer receiving sheet wasplaced in face-toface contact with the dampened paper. The sandwich washeated on a 140 C. mandrel for 2 seconds and the papers separated. Apositive, brown-black image of that on the exposed paper was on thereceiving sheet.

EXAMPLE ll The following solution was prepared:

Suocinimide l5.0 g. Sodium lsoascorbate 2.5 g. l-Phcnyl-B-pyrazolidone[.5 g. Tetraethylammonium bromide 90 g. Water 20.0 g.

This solution was dispersed in 93 g. of 7 percent ethyl cellulose intoluene.

The dispersion was coated (0.004-inch knife) over a sheet of paperhaving a fogged, direct positive, silver chloride emulsion of the typein US. Pat. No. 2,541,472 and dried. It was then exposed for 45 secondsto a line copy negative using a number 2 Photoflood with a piece ofyellow sheeting interspersed between the lamp and the negative. Thecoated paper was then heated on a 155 C. mandrel for 3 seconds and apositive reproduction of the positive image resulted. The print wasstable to fluorescent light with no deterioration of the image and noincrease in background.

EXAMPLE 12 The following solution was prepared: Succinimide 10.0 g.Methane sulfonamide 5.0 g. Water 20.0 ml.

l-Phenyl-S-pyrazolidone l.5 g. Sodium lsoascorbate 2.5 g.

I Tetraethylammonium bromide l0.0 g.

This solution was dispersed in 93 g. of 7 percent ethyl cellulose intoluene.

The dispersion was coated (0.006-inch knife) over a sheet of paperhaving a gelatino-silver chloride emulsion and dried. It was thenexposed to a line copy negative (10 seconds, 40 watt bulb) and heated ona 155 C. mandrel for three seconds. A brown image resulted with anoff-white background. The paper was incubated at 100 percent relativehumidity, 75 C., for 24 hours with no deterioration of the image and noincrease in the background.

EXAMPLE l3 The following solution was prepared: Succinirnide 6.0 g.Sulflmide 2.0 g. Water 3.0 g. Tetnpropylammonium iodide 8.0 g.

This solution was dispersed in 35 g. of 14 percent ethyl cellulose intoluene.

The dispersion was coated (0.004-inch knife) on a photographic paperwhich contained AgCl, gelatin, succinimide,lphenyl-4-methyl-3-pyrazolidone and sodium isoascorbate. The paper wasthen exposed to a line copy negative (30 seconds, 40 watt bulb) andheated on a 155 C. mandrel for 4 seconds. A black image resulted with ayellow background. The paper was exposed to fluorescent light for 24hours with no deterioration of the image and no increase in background.This paper, when not coated with the dispersion, will give an excellentimage after exposure and heating, but the background will darken onexposure to visible light.

EXAMPLE 14 A silver halide emulsion was prepared as follows: (a) 14 g.of a silver chloride coagulum, which contains 15 g. of gelatin and onemole of silver in each 370 g. of emulsion, was dispersed in g. ofgelatin which also contained 7 g. of succinimide; (b) a solution wasmade as follows:

Succinimide l5.0 g. Water 20.0 g. l-Phenyl-B-pyrazolidone l.5 g. Sodiumlsoascorbate 2.5 g. Tetrapropylammonium iodide 8.0

Ten parts of (a) were mixed with five parts of (b) and coatedimmediately on gelatin-subbed poly(ethylene terephthalate) film support.After drying, the coating was given an exposure of 5 seconds with anumber 2 Photoflood (12-inch distance) and then heated for 10 seconds ona l55 C. mandrel. A developed and stabilized image resulted.

EXAMPLE 15 The following solution was prepared:

Succinimide l5.0 g. Sodium lsoascorbate 2.5 g. l-Phenyl-J-pyrazolidonel.5 g. n-Butyltriphenylphosphonium bromide l0.0 g. Water 20.0 g.

This solution was dispersed in 93 g. of 7 percent ethyl cellulose intoluene.

The dispersion was coated over paper having a gelatinosilver chlorideemulsion using an 0.008-inch knife. The dried coating was exposed to aline image and heated for 5 seconds at C. A developed and stabilizedimage resulted.

EXAMPLE 16 The following solution was prepared:

Suecinimide l5.0 g. Sodium lsoascorbate 2.5 g. l-Phenyl-S-pyrazolidone1.5 g. Tetraethylphosphonium bromide 9.0 g. Water 20.0 ml.

EXAMPLE 17 The following solution was prepared:

Succinimide l5.0 g. Sodium lsoascorbate 2.5 g. l-Phenyl-3-pyrazolidonel.5 g. Phenyltrimethylphosphonium bromide 7.0 Water 20.0 ml.

This solution was dispersed in 93 g. of 7 percent ethyl cellulose intoluene.

The dispersion was coated over paper having a gelatinosilver chlorideemulsion using a 0.008-inch knife. The dried coating was exposed to aline image and heated at l55 C. for 5 seconds. A developed andstabilized image resulted.

EXAMPLE 18 The following solution was prepared: Succinimide l5.0 g.Sodium lsoascorbate 2.5 g l-Phenyl-Iipyrazolidone L5 3'l'rimethylsult'onium bromide 5.0 g. Water 20.0 ml

This solution was dispersed in 93 g. of 7 percent ethyl cellulose intoluene.

The dispersion was coated over paper having a gelatinosilver chlorideemulsion using a 0.006inch knife. The dried coating was exposed to aline image and heated at l40 C. for

5 seconds. A developed and stabilized image resulted.

EXAMPLE 19 The following solution was prepared:

Succinimide [5.0 g. Sodium lsoascorbate 2.5 g. l-Phenyl-3- yrazolidone1.5 g. Ethyl dimethylsulfoxonium bromide 8.3 g. Water 20.0 ml.

EXAMPLE 20 -Preparation of a Dry Processing Web The following solutionwas prepared:

Succinimide 10.0 g. Urea 10.0 g. Sodium Isoascorbate 2.5 g.l-PhenyH-pyrazolidone 1.5 g. Tetraethylammonium bromide [0.0 g. Water20.0 ml.

This solution was dispersed in 45 g. of a 15 percent toluene solution ofcellulose acetate-butyrate.

The dispersion was coated over gel-subbed paper support using a0.0l-inch knife. A piece of paper having a gelatinosilver chlorideemulsion was exposed to a line copy negative and then placedface-'to-face with the paper web. The sandwich was heated on a 155 C.mandrel (paper side down) for seconds. When separated, a developed andstabilized image was formed on the previously exposed paper. EXAMPLE 2]This example makes use of tropolone boron halides as complexing agentsin nonaqueous systems.

Five grams (0.02 mole) of boron bromide was dissolved in 25 ml. ofchloroform under a nitrogen atmosphere. A second solution consisting of4.9 g. (0.04 mole) of tropolone in 120 ml. of chloroform was alsoprepared under nitrogen. The two solutions'were mixed and refluxed for 3hours. During this time a steady stream of nitrogen gas passed throughthe reaction mixture to carry off the HBr that is formed during thereaction. The reaction mixture was placed in an evaporating dish andleft overnight in a dry box.

The product, a yellow solid, was recrystallized from water to give 5.6g. of tropolone boron bromide.

Tropolone boron bromide is soluble in water, forrnamide and moltensuccinimide. A 5 percent solution in water showed no tendency todissolve silver chloride or silver bromide. A 5 percent solution informamide (or molten succinimide) dissolved silver chloride and silverbromide very readily.

EXAMPLE 22 This example makes use of tropolone silicon chloride as asilver halide complexing agent.

In an analogous procedure, silicon tetrachloride (4.6 g., 0.028 mole) in50 ml. chloroform was added to a solution of tropolone (10 g., 0.08mole) in ml. of chloroform. After the addition, a rapid stream ofnitrogen was passed through the mixture at reflux for 7 hours. Afterthis time the evolution of HC! had ceased and awhite solidflseparated.This was isolated by filtration and recrystallized from water to give102 g. of tropolone silicon chloride (T si cl' 1 tropolone siliconchloride Anal. Calcd. for T,Si*Cl:

Found:

A 10 percentsolution in water showed no tendency to dissolve silverchloride or silver bromide. A 10 percent solution in formamide (ormolten succinimide) dissolved silver chloride.

EXAMPLE 23 This example illustrates a quaternary halide-succinimidemixture for silver halide stabilizing processing at room temperature. Alarge amount of water was used to lower the crystallization point of themixture.

The following solution can be used as a bath or as a surface applicationusing a hopper or roller.

Succinirnide 26.0 g. Tetraethylammonium bromide 20.0 Water l20.0 ml.Dimelhyl sulfoxide l5.0 ml. Isooctylphenyl polyethoxyethanol (2% aqueousA fine grain silver chloride paper was exposed and developed by asurface application of Kodak D-72 Developer 1:1 and then was stabilizedby passing it over a roller dipped into the above stabilizing solution.After drying with warm air for 20-30 seconds, the samples werelight-stable. lncubations for 3 days at 25 C., 75 percent relativehumidity, showed no signs of image fading. Also, there was no sign oftackiness under the high humidity conditions.

Although the invention has been described in considerable detail withparticular reference to certain preferred embodiments thereof,variations and modifications can be effected within the spirit and scopeof the invention as described hereinbefore and as defined in theappended claims.

We claim:

1. A photographic silver halide stabilizing composition consistingessentially of a solution of an organic silver halide complexing agentin a silver halide stabilizing concentration of about 5 percent to about40 percent by weight of said solution in a solvent which comprisesformamide, dimethylsulfoxide, dimethylformamide, succinimide, sulfamide.urea or acetamide, said complexing agent being an organic sulfoniumhalide, an organic ammonium halide, an organic phosphonium halide,tropolone boronium halide, tropolone siliconium halide, or mixturesthereof.

2. The composition of claim 1 wherein said complexing agent istetraethylammonium bromide, 2-hydroxy-ethyltrimethlammonium bromide,tetrapropylammonium iodide, tetra-ethylphosphonium bromide, ortrimethylsulfonium bromide.

3. The composition of claim 1 wherein the solvent is succinimide and thecomplexing agent is tetraethyl-ammonium bromide or tetraethylphosphoniumbromide.

4. The composition of claim 1 wherein said complexing agent istetraethylammonium bromide.

5. The composition of claim 1 which also contains a polymeric binder.

6. A process comprising developing a latent image in an exposedphotographic silver halide element and stabilizing the undevelopedphotographic silver halide, in said element with a solution consistingessentially of an organic silver halide complexing agent in a silverhalide stabilizing concentration of about 5 to about 40 percent byweight of the solution; said complexing agent being an organic sulfoniumhalide, an organic ammonium halide, an organic phosphonium halide, atropolone boronium halide, a tropolone siliconium halide, or mixturesthereof in water or a low-melting, nonaqueous solvent.

7. The process of claim 6 wherein complexed silver halide is removedfrom the element by washing.

8. The process of claim 6 wherein the solvent is formamide,dimethylformamide, dimethyl sulfoxide, succinimide, sulfamide,acetamide, urea, or water.

9. The process of claim 6 wherein said complexing agent istetraethylammonium bromide, 2-hydroxyethyltri-methylammonium bromide,tetrapropylammonium iodide, tetraethylphosphonium bromide, ortrimethylsulfonium bromide.

10. The process of claim 6 wherein said solution is heated to about900C. to about 155 C.

11. The process of claim 10 wherein the solvent is succinimide,sulfamide, urea, acetamide, or water.

12. The process of claim 10, wherein the solvent is succinimide and thecomplexing agent is tetraethylammonium bromide or tetraethylphosphoniumbromide.

13. The process of claim 12 wherein said complexing agent istetraethylammonium bromide.

14. A photographic silver halide stabilizing composition consistingessentially of a solution of an organic silver halide complexing agent,in a silver halide stabilizing concentration of about 5 percent to about40 percent by weight of said solution, in a solvent which comprises aformamide, dimethylsulfoxide, dimethylformamide, Lmethylformamide,succinimide, Lsulfamide, urea or acetamide, said complexing agent being(a) a compound of the formula:

wherein A is S; A is N or P; R R and R are lower alkyl; R is lower alkylor phenyl; X is a halide ion;

b. tropolone boronium halide; or

c. tropolone siliconium halide.

15. The composition of claim 1 comprising a photographic silver halidedeveloping agent.

16. A process comprising developing a latent image in an exposedphotographic silver halide element and stabilizing the underdevelopedphotographic silver halide in said element, with a solution consistingessentially of an organic silver halide complexing agent, in a silverhalide stabilizing concentration of about 5 percent to about 40 percentby weight of said solution, said complexing agent being (a) a compoundof the formula:

wherein A is S; A is P or N; R,, R and R are lower alkyl; R, is loweralkyl or phenyl; X is a halide ion;

b. tropolone boronium halide; or c. tropolone siliconium halide, ormixtures thereof, in water or a low-melting, nonaqueous solvent.

Ii/3? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3, 5,51 Dated October 26, 1971 Inventor) Joseph S. Yudelson and RandallE. Mack It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

In the Abstract, line L|., "of mixtures should read -----or mixtures---.

In Column 5, line 73, "L .0.0 g. X" should read go """o In Column 10,line 12, "(T Si Cl should read --(T Si Cl")---.

In Column 10, line 31, "T Si C1 should read ---T Si Cl"---.

In Column 10, line 51, after "polyethoxyethanol" insert ---surfactant--.

In Column 10, line 52, after "2% aqueous" insert --solution)---.

In Column 10, line 56, after "it" insert --twioe--.

In the Claims:

In Column 11, line 6, "trimethlammonium" should read---tr-imethylammonium---.

Page 2 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3, 5,510 Dated October 26, 1971 Inventor) Joseph S. Yudelson and RandallE. Mack It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

In Column 11, line 3 900C. should read ---90c.---.

In Column 12, line 8, "Imethylformamide" should read -methylformamide--.

In Column 12, line 9, Lsulafamide" should read --sulfamide--.

In Column 12, line 25, "underdeveloped should read -undeveloped---.

Signed and sealed this luth day of November 197?.

(SEAL) Attest:

EDwARD M.FLETCI-H5JR,JR. ROBERT GOTTSCHALK Attestlng OfficerCommissioner of Patents

2. The composition of claim 1 wherein said complexing agent istetraethylammonium bromide, 2-hydroxy-ethyltrimethlammonium bromide,tetrapropylammonium iodide, tetra-ethylphosphonium bromide, ortrimethylsulfonium bromide.
 3. The composition of claim 1 wherein thesolvent is succinimide and the complexing agent is tetraethyl-ammoniumbromide or tetraethylphosphonium bromide.
 4. The composition of claim 1wherein said complexing agent is tetraethylammonium bromide.
 5. Thecomposition of claim 1 which also contains a polymeric binder.
 6. Aprocess comprising developing a latent image in an exposed photographicsilver halide element and stabilizing the undeveloped photographicsilver halide, in said element with a solution consisting essentially ofan organic silver halide complexing agent in a silver halide stabilizingconcentration of about 5 to about 40 percent by weight of the solution;said complexing agent being an organic sulfonium halide, an organicammonium halide, an organic phosphonium halide, a tropolone boroniumhalide, a tropolone siliconium halide, or mixtures thereof in water or alow-melting, nonaqueous solvent.
 7. The process of claim 6 whereincomplexed silver halide is removed from the element by washing.
 8. Theprocess of claim 6 wherein the solvent is formamide, dimethylformamide,dimethyl sulfoxide, succinimide, sulfamide, acetamide, urea, or water.9. The process of claim 6 wherein said complexing agent istetraethylammonium bromide, 2-hydroxyethyltri-methylammonium bromide,tetrapropylammonium iodide, tetraethyl-phosphonium bromide, ortrimethylsulfonium bromide.
 10. The process of claim 6 wherein saidsolution is heated to aBout 90* C. to about 155* C.
 11. The process ofclaim 10 wherein the solvent is succinimide, sulfamide, urea, acetamide,or water.
 12. The process of claim 10 wherein the solvent is succinimideand the complexing agent is tetraethylammonium bromide ortetraethylphosphonium bromide.
 13. The process of claim 12 wherein saidcomplexing agent is tetraethylammonium bromide.
 14. A photographicsilver halide stabilizing composition consisting essentially of asolution of an organic silver halide complexing agent, in a silverhalide stabilizing concentration of about 5 percent to about 40 percentby weight of said solution, in a solvent which comprises formamide,dimethylsulfoxide, dimethylformamide, succinimide, sulfamide, urea oracetamide, said complexing agent being (a) a compound of the formula:15. The composition of claim 1 comprising a photographic silver halidedeveloping agent.
 16. A process comprising developing a latent image inan exposed photographic silver halide element and stabilizing theunderdeveloped photographic silver halide in said element, with asolution consisting essentially of an organic silver halide complexingagent, in a silver halide stabilizing concentration of about 5 percentto about 40 percent by weight of said solution, said complexing agentbeing (a) a compound of the formula: